The present invention relates to a temperature-setting device which can be used to provide a desired temperature to a minimal quantity of fluid circulating in a closed system.
Also the present invention relates to a thermal treatment apparatus including such temperature-setting device for selectively treating a targeted tissue by applying fluid-induced thermal therapy, as disclosed in U.S. Pat. No. 5,257,977 and patent application Ser. No. 08/212,197.
Fluid induced thermal therapy is based on localized heating of a targeted tissue to a predetermined temperature by means of circulating fluid, while keeping the temperature of adjacent healthy tissues unchanged. Relative to therapy methods which use laser, microwave, radiofrequency and ultrasound to produce heat within a tissue, the fluid-induced thermotherapy allows better control of the temperature and the limits of the treated site.
Alternatively, a thermal treatment apparatus according to the present invention may be used for selectively preserving a portion of a tissue treated by cryosurgery, by selectively heating that portion of the tissue.
Various attempts have been made to provide devices for heating an amount of fluid circulating in a closed systems such as fluid-induced thermal therapy systems. Prior art includes heating bath circulators and a heater based on a container serving as a water reservoir. An example is disclosed in U.S. patent application Ser. No. 08/212,197.
However, such configurations consume a considerable amount of energy, since a large quantity of fluid has to be heated (or cooled). Moreover, a considerable damage may be caused in the event of system's failure, by the leakage of a large quantity of fluid into the body cavity.
There is thus a widely recognized need for, and it would be highly advantageous to have, a device which can provide a desired temperature to a minimal quantity of fluid which circulates in a closed system such as fluid-induced thermal therapy system.
It would be further advantageous to have such device which allows to alternately heat and cool a component of such closed system by alternately placing such component in embodiments of the device functioning as heaters and coolers.
It would be further advantageous to have a thermal treatment apparatus for selectively treating a targeted tissue by fluid-induced thermal therapy, which uses a minimal quantity of circulating fluid and therefore consumes minimal energy for heating (or cooling) the fluid, and minimizes the possible damage in the event of fluid leakage.